Diesel exhaust fluid mixing body using variable cross-section switchback arrangement

ABSTRACT

An aftertreatment system includes a filter configured to receive an exhaust gas and a selective catalytic reduction (SCR) system configured to treat the exhaust gas. A body mixer is disposed downstream of the filter and upstream of the SCR system. The body mixer includes a housing defining an internal volume and including at least a first passageway, a second passageway, and a third passageway. The first passageway receives a flow of the exhaust gas from the filter and directs the flow of the exhaust gas towards the second passageway. The second passageway redirects the flow in a second direction opposite the first direction towards the third passageway. The third passageway redirects the flow in a third direction opposite the second direction towards the SCR system. An injection port is disposed on a sidewall of the housing and configured to communicate an exhaust reductant into the internal volume.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of priority to U.S.Provisional Patent Application No. 62/067,168, filed Oct. 22, 2014, thecontents of which are incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to exhaust aftertreatmentsystems for use with internal combustion (IC) engines.

BACKGROUND

During the combustion process in an IC engine (e.g., a diesel-poweredengine), sulfur is concurrently formed with carbon monoxide (CO) andhydrocarbons (HC) as various sulfur oxides (SO_(x)). Typically, 97-99%of the total amount of SO_(x) present in exhaust gas includes sulfurdioxide (SO₂) and 1-3% includes sulfur trioxide (SO₃). Thus, fuels withhigher sulfur content tend to produce higher amounts of SO₃. Forexample, fuel with sulfur content of 1000 ppm may form approximately 1-3ppm SO₃.

Exhaust aftertreatment systems are used to receive and treat exhaust gasgenerated by IC engines. Conventional exhaust gas aftertreatment systemsinclude any of several different components to reduce the levels ofharmful exhaust emissions present in exhaust gas. For example, certainexhaust aftertreatment systems for diesel-powered IC engines include aselective catalytic reduction (SCR) catalyst to convert NO_(x) (NO andNO₂ in some fraction) into harmless nitrogen gas (N₂) and water vapor(H₂O) in the presence of ammonia (NH₃). Generally in such conventionalaftertreatment systems, an exhaust reductant, (e.g., a diesel exhaustfluid such as urea) is injected into the aftertreatment system toprovide a source of ammonia, and mixed with the exhaust gas to partiallyreduce the SOx and/or the NOx gases. The reduction byproducts of theexhaust gas are then fluidically communicated to the catalyst includedin the SCR aftertreatment system to decompose substantially all of theSOx and NOx gases into relatively harmless byproducts which are expelledout of such conventional SCR aftertreatment systems.

SO₃ can react with ammonia to produce ammonium sulfate ((NH₄)₂SO₄) andammonium bisulfate (NH₄HSO₄). In conventional selective catalyticreduction systems for aftertreatment of exhaust gas (e.g., dieselexhaust gas) urea is often used as a source of ammonia for reducing SOxand NOx gases included in the exhaust gas of IC engines (e.g., dieselexhaust gas). The urea or any other source of ammonia communicated intoconventional aftertreatment systems can be deposited on sidewalls and/orcomponents of the aftertreatment system. Furthermore, the efficiency ofthe aftertreatment system can depend on the mixing of the exhaustreductant with the exhaust gas, the temperature of the exhaust gas,and/or the backpressure experienced by the exhaust gas.

SUMMARY

Embodiments described herein relate generally to exhaust aftertreatmentsystems for use with IC engines, and in particular to exhaustaftertreatment systems that include a body mixer for mixing an exhaustreductant with an exhaust gas. In some embodiments, an aftertreatmentsystem includes a filter configured to receive an exhaust gas andsubstantially remove any particulate from the exhaust gas as it flowsthrough the filter. The aftertreatment system also includes a selectivecatalytic reduction (SCR) system positioned downstream of the filter andconfigured to treat the exhaust gas flowing through the SCR system. Abody mixer is disposed downstream of the filter and upstream of the SCRsystem. The body mixer includes a housing defining an internal volume.The housing is structured to include at least a first passageway, asecond passageway, and a third passageway. The first passageway isstructured to receive a flow of the exhaust gas from the filter anddirect the flow of the exhaust gas towards the second passageway. Thesecond passageway is structured to redirect the flow in a seconddirection substantially opposite the first direction towards the thirdpassageway. The third passageway is structured to redirect the flow in athird direction substantially opposite the second direction towards theSCR system. An injection port is disposed on a sidewall of the housingand configured to communicate an exhaust reductant into the internalvolume.

In some embodiments, the body mixer is configured to mix the exhaustreductant with the exhaust gas as the exhaust gas flows through thefirst passageway, the second passageway, and the third passageway. Inone embodiment, a first partition wall and a second partition wall aredisposed in the internal volume defined by the aftertreatment system,and are oriented to define the first passageway, the second passagewayand the third passageway. In another embodiment, the first partitionwall and the second partition wall are disposed substantially parallelto each other. In yet another embodiment, the first partition wall andthe second partition wall are substantially arcuate.

In another set of embodiments, a mixer for use in an aftertreatmentsystem for mixing a reductant inserted into the aftertreatment systemwith an exhaust gas flowing through the aftertreatment system comprisesa housing defining an internal volume. The housing defines at least afirst passageway, a second passageway and a third passageway. The firstpassageway is structured to receive a flow of the exhaust gas anddirects the flow in a first direction towards the second passageway. Thesecond passageway is structured to redirect the flow in a seconddirection substantially opposite the first direction towards the thirdpassageway. The third passageway is structured to redirect the flow in athird direction substantially opposite the second direction towards anoutlet of the housing. An injection port is defined on a sidewall of thehousing and structured to allow a reductant to be inserted into thehousing.

In yet another set of embodiments, a method of promoting mixing of areductant with an exhaust gas flowing through an aftertreatment systemincluding at least a SCR system comprises positioning a mixer upstreamof the SCR system. The mixer includes a housing defining an internalvolume. The housing includes at least a first passageway, a secondpassageway, a third passageway and an injection port defined on asidewall of the housing proximate to the first passageway. A reductantis inserted into the first passageway via the injection port. An exhaustgas is flowed into the first passageway. The first passageway isstructured to direct the flow in a first direction towards the secondpassageway. The second passageway is structured to redirect the flow ina second direction substantially opposite the first direction towardsthe third passageway. The third passageway is structured to redirect theflow in a third direction substantially opposite the second directiontowards the SCR system.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several implementations in accordance withthe disclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

FIG. 1 is a schematic block diagram of an aftertreatment system thatincludes a body mixer, according to an embodiment.

FIG. 2A is a front view of a body mixer, according to an embodiment, andFIG. 2B shows a side cross-section view of the body mixer of FIG. 2Ataken along the line A-A.

FIG. 3A is a front view of a body mixer according to an embodiment, andFIG. 3B is a side cross-section view of the body mixer of FIG. 3A takenalong the line B-B.

FIG. 4 is a side cross-section view of a body mixer, according toanother embodiment.

FIG. 5 is a side cross-section view of a body mixer, according to a yetanother embodiment.

FIG. 6 is a side cross-section view of a body mixer, according to astill another embodiment.

FIG. 7 is a schematic flow diagram of an embodiment of a method tofacilitate mixing of a reductant with an exhaust gas using a mixer.

Reference is made to the accompanying drawings throughout the followingdetailed description. In the drawings, similar symbols typicallyidentify similar components, unless context dictates otherwise. Theillustrative implementations described in the detailed description,drawings, and claims are not meant to be limiting. Other implementationsmay be utilized, and other changes may be made, without departing fromthe spirit or scope of the subject matter presented here. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the figures, can bearranged, substituted, combined, and designed in a wide variety ofdifferent configurations, all of which are explicitly contemplated andmade part of this disclosure.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Embodiments described herein relate generally to exhaust aftertreatmentsystems for use with IC engines, and in particular to exhaustaftertreatment systems that include a body mixer for mixing an exhaustgas with an exhaust reductant. Embodiments described herein may provideseveral advantages over conventional aftertreatment systems including,for example: (1) efficient mixing of an exhaust reductant (e.g., adiesel exhaust fluid such as urea) with an exhaust gas (e.g., a dieselexhaust gas) in a body mixer; (2) reducing exhaust reductant deposits(e.g., urea deposits) on a sidewall of the body mixer; (3) reducing abackpressure of the exhaust gas flowing through the aftertreatmentsystem, thereby improving fuel economy and reducing operating cost; (4)increasing a residence time of the exhaust gas within the aftertreatmentsystem allowing better mixing of the exhaust reductant with the exhaustgas; (5) reducing the space required for mixing of the exhaust gas withthe exhaust reductant; (6) improving heat retention; and (7) reductionin overall cost.

FIG. 1 shows an aftertreatment system 100 for treating an exhaust gas(e.g., a diesel exhaust gas) produced by an IC engine (e.g., a dieselengine). The aftertreatment system 100 includes a filter 110, a bodymixer 130, and a selective catalytic reduction (SCR) system 150.

The filter 110 is configured to receive a flow of an exhaust gas (e.g.,a diesel exhaust gas) from an IC engine. The filter 110 can comprise anysuitable filter (e.g., a diesel particulate filter) configured to filterand remove any particulates entrained within the exhaust gas flow, andprevent such particulates from entering the SCR system 150. Suchparticles can include, for example, dust, soot, organic particles,crystals, or any other solid particulates present in the exhaust gas.The filter 110 can include a housing made of a strong and rigid materialsuch as, for example, high density polypropylene (HDPP) which can definean internal volume to house a filter element. Any suitable filterelement can be used such as, for example, a cotton filter element, anacrylonitrile butadiene styrene (ABS) filter element, any other suitablefilter element or a combination thereof. The filter element can have anysuitable pore size, for example, about 10 microns, about 5 microns, orabout 1 micron.

In some embodiments, the aftertreatment system 100 may not include thefilter 110. In such embodiments, a diesel oxidation catalyst (DOC) canbe included in the aftertreatment system 100 in place of the filter 110.In other embodiments, the aftertreatment system 100 may not include afilter or the DOC and may be only include the SCR system 150. In suchembodiments, an exhaust pipe tube, pipe, or otherwise manifold coupledto an outlet of the IC engine can be directly coupled to an inlet of thebody mixer 130, and the SCR system 150 can be downstream of the bodymixer 130. In still other embodiments, the aftertreatment system 100 caninclude the DOC, the filter and/or any other suitable aftertreatmentcomponents.

The body mixer 130 or mixer 130 is disposed downstream of the filter 110and upstream of the SCR system 150, and fluidically couples the filter110 to the SCR system 150. The body mixer 130 includes a housing whichdefines an internal volume. The housing can be formed from a rigid, heatresistant, and/or corrosion resistant material. Suitable materials caninclude, without limitation, metals (e.g., stainless steel, iron,aluminum, alloys, etc.), ceramics, any other suitable material or acombination thereof. The housing can define a circular, square,rectangular, polygonal, oval, or any other suitable cross section.Furthermore, the length of the housing along the flow direction of theexhaust gas can be varied to increase or decrease the residence time ofthe exhaust gas within the body mixer 130.

The housing includes an inlet to receive the exhaust gas form the filter110, and an outlet to deliver the exhaust gas to the SCR system 150. Insome embodiments, the inlet and the outlet can have substantially thesame cross-section (e.g., width or diameter). In other embodiments, theoutlet can have a larger cross-section than the inlet, for example, whenthe SCR system 150 has a larger cross-section than the filter 110. Insome embodiments, the outlet can have a large cross-section to serve asa diffuser, for example, to reduce a flow velocity of the exhaust gasinto the SCR system 150. This can, for example, reduce the back pressureexperienced by the exhaust gas flowing through the SCR system 150.

The housing is structured to include at least a first passageway, asecond passageway, and a third passageway. In other embodiments, thehousing of the body mixer 130 can be structured to include even morepassageways, for example, four, five, six or even more passageways. Thepassageways can be defined in the housing using any suitable means. Insome embodiments, a first partition wall and a second partition wall canbe disposed in the inner volume defined by the housing. The firstpartition wall and the second partition wall can be oriented to definethe first passageway, the second passageway, and the third passageway.In one embodiment, the first passageway and the second passageway can bedisposed substantially parallel to each other. In other embodiments, thefirst partition wall and the second partition wall can be substantiallyarcuate. In yet other embodiments, the first partition wall and thesecond partition wall can be substantially non-arcuate, and disposed andoriented at a non-zero angle with respect to the inlet flow direction.

The first passageway is structured to receive a flow of exhaust gas fromthe filter 110 and direct the flow in a first direction towards thesecond passageway. In some embodiments, the flow in the first directioncan be substantially parallel to, or otherwise in line with an inletflow direction of the exhaust gas into the first passageway, forexample, when the first passageway is defined substantially parallel tothe inlet flow. In such embodiments, the first partition wall can bedisposed substantially parallel to the direction of flow. In otherembodiments, the flow in the first direction can be orthogonal to theinlet flow direction, for example when the first partition wall isdisposed orthogonal to the inlet flow direction. In yet anotherembodiment, the first passageway can be curved, for example, when thefirst partition wall is arcuate. In such embodiments, the flow in thefirst direction can substantially normal to the inlet flow andcontinuously change direction while flowing through the first passageway

The second passageway is structured to redirect the exhaust gas flow ina second direction that is different than first direction, and towardsthe third passageway. For example, the exhaust gas flow can experience achange in direction of the flow of greater than about 90 degrees (e.g.,about 100 degrees, 110 degrees, 120 degrees, 130 degrees, 140 degrees,150 degrees, 160 degrees, 170 degrees, or about 180 degrees) on enteringthe second passageway.

The third passageway is structured to redirect the flow in a thirddirection that is different than the second direction towards the SCRsystem 150. For example, the exhaust gas flow can experience a change indirection of the flow of greater than about 90 degrees (e.g., about 100degrees, 110 degrees, 120 degrees, 130 degrees, 140 degrees, 150degrees, 160 degrees, 170 degrees, or about 180 degrees) on entering thethird passageway from the second passageway.

As described herein, the first passageway, the second passageway, thethird flow passageway define a single seamless flow path for the exhaustgas to flow through the body mixer 130. In some embodiments, thetransition from the first passageway to the second passageway, and/orfrom the second passageway to the third passageway can be defined by achange in direction of the exhaust gas flow of greater than about 90degrees (e.g., about 100 degrees, 110 degrees, 120 degrees, 130 degrees,140 degrees, 150 degrees, 160 degrees, 170 degrees, or about 180degrees). In other words, in such embodiments the second passagewaystarts at a location within the internal volume where the exhaust gasflow travelling through the first passageway experiences a change inflow direction of great than about 90 degrees. Similarly, the thirdpassageway starts at a location within the internal volume where theexhaust gas flow travelling through the second passageway experiences achange in flow direction of great than about 90 degrees.

In other embodiments, the transition from the first passageway to thesecond passageway, and/or from the second passageway to the thirdpassageway can be defined by the partition walls. For example, the firstpassageway can be defined as the portion of the internal volume definedby a surface of a sidewall of the housing, and a first surface of thefirst partition wall. Furthermore, a portion of the internal volume thatwould have been bounded by the first surface of the first partitionwall, if the partition wall extended from a first sidewall of thehousing to a second sidewall of the housing (or a surface of the secondpartition wall) can also be included in the first passageway. The secondpassageway and the third passageway can be similarly defined. Theseconcepts will be understood more clearly with respect to thespecifications of the specific embodiments describe herein.

An injection port is disposed on a sidewall of the housing of the bodymixer 130. The injection port is configured to communicate an exhaustreductant into the internal volume. For example, the injection port canbe disposed in a sidewall which defines the first passageway. Theexhaust reductant can thus be communicated into the first passageway.The body mixer is configured to mix the exhaust gas with the exhaustreductant as the exhaust gas flows through the first passageway, thesecond passageway, and thereon to the third passageway. The body mixercan thus increase the residence time of the exhaust gas and the exhaustreductant within the internal volume defined by the body mixer 130. Thiscan enable efficient mixing of the exhaust reductant with the exhaustgas, reduce backpressure, reduce exhaust reductant deposits (e.g., ureadeposits) within the body mixer, and or maintain a temperature of theexhaust gas as it flows through the body mixer 130 in the SCR system150.

In some embodiments, the exhaust gas can include a diesel exhaust gasand the exhaust reductant can include a diesel exhaust fluid. The dieselexhaust fluid can include urea, an aqueous solution of urea, or anyother fluid that includes ammonia, by products, or any other dieselexhaust fluid as is known in the arts (e.g., the diesel exhaust fluidmarketed under the name ADBLUE®).

The SCR system 150 is configured to treat an exhaust gas (e.g., a dieselexhaust gas) flowing through the SCR system 150. The exhaust reductantreacts with the exhaust gas to at least partially reduce one or morecomponents of the gas (e.g., SOx and NOx), or facilitate reduction ofthe one or more components in the presence of one or more catalysts.

The SCR system 150 includes one or more catalysts formulated toselectively reduce the exhaust gas. Any suitable catalyst can be usedsuch as, for example, platinum, palladium, rhodium, cerium, iron,manganese, copper, vanadium based catalyst, any other suitable catalyst,or a combination thereof. The catalyst can be disposed on a suitablesubstrate such as, for example, a ceramic (e.g., cordierite) or metallic(e.g., kanthal) monolith core which can, for example, define a honeycombstructure. A washcoat can also be used as a carrier material for thecatalysts. Such washcoat materials can include, for example, aluminumoxide, titanium dioxide, silicon dioxide, any other suitable washcoatmaterial, or a combination thereof. The exhaust gas (e.g., dieselexhaust gas) can flow over and about the catalyst such that any SOx orNOx gases included in the exhaust gas are further reduced to yield anexhaust gas which is substantially free of carbon monoxide, SOx and NOxgases.

In some embodiments, the body mixer can include passageways that havecross-sections defining a sector of a circle. For example, FIG. 2A showsa front view, and FIG. 2B shows a side cross section view of a bodymixer or mixer 230 which can be included in an aftertreatment system,for example, the aftertreatment system 100 or any other aftertreatmentsystem described herein.

The body mixer includes a housing 231 defining an internal volume. Thehousing 231 defines a circular cross-section, but can be configured todefine any other cross-section (e.g., square, rectangular, polygonal,oval, etc.). A first partition wall 232 a, a second partition wall 232b, and a third partition wall 232 c (collectively referred to as“partition walls 232) are disposed in the internal volume. The partitionwalls 232 are disposed and oriented to define a first passageway 234, asecond passageway 236, and third passageway 238. The first passageway234, the second passageway 236, and the third passageway 238 are influidic communication with each other and define a continuous flow pathfor the exhaust gas to flow. As shown in FIG. 2A, each of the firstpassageway 234, the second passageway 236, and the third passageway 238is structured to have a cross-section which resembles a sector of acircle.

As shown in FIG. 2A, a first partition wall first end of the firstpartition wall 232 a, a second partition wall first end of the secondpartition wall 232 b and a third partition wall first end of the thirdpartition wall 232 c are in contact with each other proximate to acentral axis of the housing 231. The first partition wall 232 a, thesecond partition wall 232 b and the third partition wall 232 c extendaway from the central axis and each other so that a first partition wallsecond end of the first partition wall 232 a, a second partition wallsecond end of the second partition wall 232 b and a third partition wallsecond end of the third partition wall 232 c are in contact with asidewall of the housing 231 at different locations, thereby dividing thehousing into the first passageway, the second passageway and the thirdpassageway.

An injection port 240 is disposed on a sidewall of the body mixer 230which defines the first passageway 234. The injection port 240 isconfigured to communicate an exhaust reductant (e.g., a diesel exhaustfluid such as urea) into the first passageway 234 and allow mixing ofthe exhaust reductant with the exhaust gas as it flows through the bodymixer.

The first passageway 234 is structured to receive a flow of exhaust, forexample, from a filter (e.g., the filter 110) and direct the flow in afirst direction towards the second passageway 236, as shown in FIG. 2B.The second passageway 236 is structured to redirect the exhaust gas flowin a second direction different than the first direction, and towardsthe third passageway 238. As shown in FIG. 2B, the exhaust gas canexperience a change in direction of the flow of exhaust gas of greaterthan about 90 degrees as it enters the second passageway 236. Inparticular embodiments, the second direction may be substantiallyopposite the first direction.

The third passageway 238 is structured to redirect the flow of exhaustgas in a third direction that is different than the second direction.For example, the exhaust gas flow can experience a change in directionof greater than about 90 degrees as it enters the third passageway 238.In particular embodiments, the third direction may be substantiallyopposite the second direction. The third passageway 238 can be influidic communication with an SCR system (e.g., the SCR system 150) andcommunicate the exhaust gas mixed with the reductant to the SCR system.

In some embodiments, a body mixer can include partition walls thatdefine passageways, and are disposed parallel to a direction of flow ofan exhaust gas. For example, FIG. 3A shows a front view, and FIG. 3Bshows a side cross-section view of a body mixer or mixer 330. The bodymixer 330 can be included in an aftertreatment system, for example, theaftertreatment system 100, or any other aftertreatment system describedherein.

The body mixer includes a housing 331 defining an internal volume. Thehousing 331 defines a circular cross-section, but can be configured todefine any other cross-section (e.g., square, rectangular, polygonal,oval, etc.). A first partition wall 332 a and a second partition wall332 b (collectively referred to as “partition walls 332) are disposed inthe internal volume. Each partition wall 332 is disposed parallel to adirection of exhaust gas flow but in different planes, so that the firstpartition wall 332 a and the second partition wall 332 b are parallel toeach other. The partition walls 332 are disposed and oriented to definea first passageway 334, a second passageway 336, and third passageway338. The first passageway 334, the second passageway 336, and the thirdpassageway 338 are in fluidic communication with each other and define acontinuous flow path for the exhaust gas to flow.

As shown in FIG. 3B, a first end of the first partition wall 332 a orfirst partition wall first end is in contact or otherwise flush with afirst sidewall of the housing 331. A second end 333 a of the firstpartition wall 332 a or first partition wall second end is distal from asecond sidewall of the housing 331 opposite the first sidewall. Incontrast, a first end of the second partition wall 332 b or secondpartition wall first end is in contact or otherwise flush with thesecond sidewall of the housing 331. A second end 333 b of the secondpartition wall 332 b or second partition wall second end is distal fromthe first sidewall of the housing 331. Furthermore, each partition wallhas a length such that the partition walls 332 partially overlap todefine each passageway. The dotted lines shown in FIG. 3B are forcontext only and meant to show the boundary of each passageway.

An injection port 340 is disposed on a sidewall of the body mixer 330which defines the first passageway 334. The injection port 340 isconfigured to communicate an exhaust reductant (e.g., a diesel exhaustfluid such as urea) into the first passageway 334 and allow mixing ofthe exhaust reductant with the exhaust gas as it flows through the bodymixer.

The first passageway 334 is structured to receive a flow of exhaust, forexample, from a filter (e.g., the filter 110) and direct the flow in afirst direction towards the second passageway 336, as shown in FIG. 3B.The exhaust reductant is injected into the first passageway 334 andmixes with the exhaust gas as it flows through each passageway. Thesecond passageway 336 is structured to redirect the exhaust gas flow ina second direction different than the first direction, and towards thethird passageway 338. As shown in FIG. 3B, the exhaust gas flow canexperience a change in direction of greater than about 90 degrees as itenters the second passageway 336. In particular embodiments, the seconddirection may be substantially opposite the first direction.

The third passageway 338 is structured to redirect the flow of exhaustgas in a third direction different than the second direction. Forexample, the exhaust gas flow can experience a change in direction ofgreater than about 90 degrees as it enters the third passageway 338. Inparticular embodiments, the third direction may be substantiallyopposite the second direction. The third passageway 338 can be influidic communication with an SCR system (e.g., the SCR system 150) andcommunicate the exhaust gas mixed with the reductant to the SCR system.

In some embodiments, a body mixer can include arcuate partition walls.For example, FIG. 4 shows a side cross-section view of a body mixer ormixer 430. The body mixer 430 can be included in an aftertreatmentsystem, for example, the aftertreatment system 100, or any otheraftertreatment system described herein.

The body mixer includes a housing 431 defining an internal volume. Thehousing 431 can define a suitable cross-section, for example, circular,square, rectangular, polygonal, oval, or any other suitablecross-section. A first partition wall 432 a and a second partition wall432 b (collectively referred to as “partition walls 432) are disposed inthe internal volume. The partition walls 432 are substantially arcuate.The partition walls 432 are disposed and oriented to define a firstpassageway 434, a second passageway 436, and third passageway 438. Thefirst passageway 434, the second passageway 436, and the thirdpassageway 438 are in fluidic communication with each other and define acontinuous flow path for the exhaust gas to flow.

As shown in FIG. 4, a first end of the first partition wall 432 a orfirst partition wall first end is in contact or otherwise flush with afirst sidewall of the housing 431. A second end 433 a of the firstpartition wall 432 a or first partition wall second end 433 a is distalfrom a second sidewall of the housing 431 and the first sidewall. Thesecond sidewall is orthogonal to the first sidewall (e.g., oriented atan angle of 75, 80, 85, 90, 95, 100 or 105 degrees with respect to thefirst sidewall. In contrast, a first end of the second partition wall432 b or second partition wall first end is in contact or otherwiseflush with the second sidewall of the housing 431. A second end 433 b ofthe second partition wall 432 b or second partition wall second end 433b is distal from the first sidewall of the housing 431. Each of thepartition walls 432 have an arc length such that the partition walls 432partially overlap to define each passageway. The dotted lines shown inFIG. 4 are for context only and meant to show the boundary of eachpassageway.

An injection port 440 is disposed on a sidewall of the body mixer 430which defines the first passageway 434. The injection port 440 isconfigured to communicate an exhaust reductant (e.g., a diesel exhaustfluid such as urea) into the first passageway 434 and allow mixing ofthe exhaust reductant with the exhaust gas as it flows through the bodymixer.

The first passageway 434 is structured to receive a flow of exhaust, forexample, from a filter 410 and direct the flow in a first directiontowards the second passageway 436, as shown in FIG. 4. The filter 410can be substantially similar to the filter 110 and is therefore, notdescribed in further detail herein. As described herein, the firstpartition wall 432 a is substantially arcuate. Thus the first passageway434, which is at least partially defined by a first sidewall of thehousing 431, and a sidewall of the first partition wall 432 a, defines asubstantially curved flow path. The exhaust reductant is injected intothe first passageway 434 and mixes with the exhaust gas as it flowsthrough each passageway.

The second passageway 436 is structured to redirect the exhaust gas flowin a second direction different than the first direction, and towardsthe third passageway 438. The second partition wall 432 b is alsoarcuate such that the second passageway 436, which is at least partiallydefined by the sidewall of the first partition wall 432 a and a sidewallof the second partition wall 432 b, defines a curved flow path. As shownin FIG. 4, the exhaust gas flow can experience a change in direction ofgreater than about 90 degrees as it enters the second passageway 436from the first passageway. In particular embodiments, the seconddirection may be substantially opposite the first direction.

The third passageway 438 is structured to redirect the flow of exhaustgas in a third direction different than the second direction. Forexample, the exhaust gas flow can experience a change in direction ofgreater than about 90 degrees as it enters the third passageway 438. Inparticular embodiments, the third direction may be substantiallyopposite the second direction. The third passageway 438, which is atleast partially defined by the sidewall of the second partition wall 432b and a second sidewall of the housing 431, defines a curved flow pathfor the exhaust gas to flow. The curved flow paths of each of the firstpassageway 434, the second passageway 436, and the third passageway 438can, for example, create vortices or changes in velocity of the exhaustgas and thereby, enhance the mixing of the exhaust gas with the exhaustreductant. The third passageway 438 can be in fluidic communication withan SCR system 450 and communicate the exhaust gas mixed with thereductant to the SCR system 450. The SCR system 450 can be substantiallysimilar to the SCR system 150 and is therefore, not described hereinfurther detail herein.

In some embodiments, a body mixer can include arcuate partition wallswhich do not overlap. For example, FIG. 5 shows a side cross-sectionview of a body mixer or mixer 530 which can be used in an aftertreatmentsystem, for example, the aftertreatment system 100 or any otheraftertreatment system described herein.

The body mixer 530 includes a housing 531 defining an internal volume.The housing 531 can be substantially similar to the housing 531 and istherefore not described in further detail herein. An injection port 540is disposed on a sidewall of the body mixer 530 which defines a firstpassageway 534 (as described herein). The injection port 540 isconfigured to communicate an exhaust reductant (e.g., a diesel exhaustfluid such as urea) into the first passageway 534 and allow mixing ofthe exhaust reductant with the exhaust gas as it flows through the bodymixer.

A first partition wall 532 a and a second partition wall 532 b(collectively referred to as “partition walls 532) are disposed in theinternal volume. The partition walls 532 are substantially arcuate. Thepartition walls 532 are disposed and oriented to define a firstpassageway 534, a second passageway 536, and third passageway 538. Thefirst passageway 534, the second passageway 536, and the thirdpassageway 538 are in fluidic communication with each other and define acontinuous flow path for the exhaust gas to flow.

As shown in FIG. 5, a first end of the first partition wall 532 a orfirst partition wall first end is in contact or otherwise flush with afirst sidewall of the housing 531. A second end 533 a of the firstpartition wall 532 a or second partition wall second end 533 a is distalfrom a second sidewall of the housing 431. In contrast, a first end ofthe second partition wall 532 b or second partition wall first end is incontact or otherwise flush with the second sidewall of the housing 531.A second end 533 b of the second partition wall 532 b or secondpartition wall second end 533 b is distal from the first sidewall of thehousing 531. Each of the partition walls 532 have an arc length suchthat the partition walls 532 do not overlap. The dotted lines shown inFIG. 5 are for context only and meant to show the boundary of eachpassageway.

The first passageway 534 is configured to receive a flow of exhaust gasfrom a filter 510, which can be substantially similar to the filter 110.The first passageway 534 directs the exhaust gas flow in a firstdirection towards the second passageway 536. The second passageway 536redirects the exhaust gas flow in a second direction different than thefirst direction towards the third passageway 538, as described withrespect to the second passageway 436 included in the body mixer 430.Similarly, the third passageway 538 redirects the exhaust gas flow in athird direction is different than the second direction towards an SCRsystem 550, as described with respect to the third passageway 438included in the body mixer 430. In particular embodiments, the seconddirection may be substantially opposite the first direction, and thethird direction may be substantially opposite the second direction.

Since there is no overlap between the partition walls 532, the entranceof the second passageway 536 and the third passageway 538 can have alarger cross-section or otherwise cross-sectional area for the exhaustgas to enter. This can result in a decrease in velocity of the exhaustgas mixed with the exhaust reductant as it enters from the firstpassageway 534 to the second passageway 536, and/or from the secondpassageway 536 to the third passageway 538. In this manner, a residencetime of the exhaust gas and exhaust reductant mixture in the body mixer530 can be increased, mixing can be enhanced, and/or backpressure can bereduced.

In some embodiments, a body mixer can include arcuate partition wallsstructured to provide a gradual change or otherwise smooth change indirection of an exhaust gas flowing through the body mixer. For example,FIG. 6 shows a side cross-section view of a body mixer or mixer 630which can be used in an aftertreatment system, for example, theaftertreatment system 100 or any other aftertreatment system describedherein.

The body mixer 630 includes a housing 631 defining an internal volume.The housing 631 can be substantially similar to the housing 431 and istherefore, not described in further detail herein. An injection port 640is disposed on a sidewall of the body mixer 630 which defines a firstpassageway 634 (as described herein). The injection port 640 isconfigured to communicate an exhaust reductant (e.g., a diesel exhaustfluid such as urea) into the first passageway 634 and allow mixing ofthe exhaust reductant with the exhaust gas as it flows through the bodymixer.

A first partition wall 632 a and a second partition wall 632 b(collectively referred to as “partition walls 632) are disposed in theinternal volume. The partition walls 632 are substantially arcuate. Thepartition walls 632 are disposed and oriented to define a firstpassageway 634, a second passageway 636, and third passageway 638. Thefirst passageway 634, the second passageway 636, and the thirdpassageway 638 are in fluidic communication with each other and define acontinuous flow path for the exhaust gas to flow.

As shown in FIG. 6, a first end of the first partition wall 632 a orfirst partition wall first end is in contact or otherwise flush with afirst sidewall of the housing 631. A second end 633 a of the firstpartition wall 632 a or first partition wall second end 633 a is distalfrom a second sidewall of the housing 431 which is opposite the firstsidewall. In contrast, a first end of the second partition wall 632 b orsecond partition wall first end is in contact or otherwise flush withthe second sidewall of the housing 631. A second end 633 b of the secondpartition wall 632 b or second partition wall send end 633 b is distalfrom the first sidewall of the housing 631. Each of the partition walls632 have an arc length such that the partition walls 632 do not overlap,as shown in FIG. 6. In other embodiments, the partition walls 632 canhave arc lengths such that the partition walls 632 at least partiallyoverlap. The dotted lines shown in FIG. 6 are for context only and meantto show the boundary of each passageway.

The first passageway 634 is configured to receive a flow of exhaust gasfrom a filter 610, which can be substantially similar to the filter 610.The first passageway 634 directs the exhaust gas flow in a firstdirection towards the second passageway 636. The second passageway 636redirects the exhaust gas flow in a second direction that is differentthan the first direction towards the third passageway 638, as describedwith respect to the second passageway 436 included in the body mixer430. Similarly, the third passageway 638 redirects the exhaust gas flowin a third direction that is different than the second direction towardsan SCR system 650, as described with respect to the third passageway 438included in the body mixer 430. Again, in particular embodiments thesecond direction is substantially opposite the first direction, and thethird direction is substantially opposite the second direction.

The partition walls 632 are structured to have an arcuate surface thatprovides a gradual or otherwise smooth change in direction for theexhaust gas flow. As shown in FIG. 6, a portion of the second partitionwall 632 b proximal to the first end of the second partition wall 632 bgradually curves away from the second sidewall of the housing 631.Similarly, a portion of the first partition wall 632 a proximal to thefirst end of the first partition wall 632 a gradually curves away fromthe first sidewall of the housing 631. Thus, there are no sharp cornersor turns, which can allow the exhaust gas mixed with the exhaustreductant to gradually and smoothly change direction as it flows fromthe first passageway 634 to the second passageway 636, and thereon tothe third passageway 638. This can reduce turbulence in the flow andthereby decrease backpressure.

In some embodiments, a body mixer can include partition walls thatinclude a plurality of small openings, holes, or slots (not shown)defined through the partition walls. For example, the partition wallsincluded in any of the body mixers 130, 230, 330, 430, 530, 630 or anyother body mixer described herein can include small openings, slots etc.(not shown) defined through the partitions walls. Such openings canallow a small portion of an exhaust gas to pass through received by thebody mixer to pass through the holes into the adjacent passageways. Thebulk of the exhaust gas, however, will still flow through thepassageways (e.g., a first passageway, a second passageway, and a thirdpassageway) of the body mixer to the SCR system coupled to the bodymixer. The openings, slots, etc. can provide a number of benefits incertain implementations such as enabling lower backpressure andproviding improved mixing of reductant.

FIG. 7 is a schematic flow diagram of an example method 700 forpromoting or facilitating mixing of a reductant (e.g., an aqueous ureasolution) with an exhaust gas (e.g., a diesel exhaust gas) flowingthrough an aftertreatment system, such as the aftertreatment system 100,which includes at least a SCR system (e.g., the SCR system 150). Bettermixing of the reductant with the exhaust gas can increase a catalyticconversion efficiency (e.g., NOx conversion efficiency of the SCRsystem, thereby reducing NOx emissions.

The method 700 includes positioning a mixer upstream of the SCR systemat 702. The mixer includes a housing defining an internal volume. Thehousing includes at least a first passageway, a second passageway, athird passageway and an injection port defined on a sidewall of thehousing proximate to the first passageway. For example, the mixer caninclude the mixer 130, 230, 330, 430, 530, 630 or any other mixerdescribed herein. In various embodiments, the mixer includes a firstpartition wall and a second wall positioned in the internal volumedefined by the housing. The first partition wall and the secondpartition wall are oriented to define the first passageway and thesecond passageway. In some embodiments, the first partition wall and thesecond partition wall are positioned parallel to each other (e.g., thefirst partition wall 332 a and the second partition wall 332 b of themixer 330, as described herein). In other embodiments, the firstpartition wall and the second partition wall are substantially arcuate(e.g., the first partition wall 432 a, 532 a or 632 a and the secondpartition wall 432 b, 532 b or 632 b of the mixer 430, 530 or 630).

A reductant is inserted into the first passageway at 704. For example, areductant insertion unit (e.g., including pumps, valves, nozzles etc.)can be in fluid communication with the injection port for inserting thereductant (e.g., an aqueous urea solution) into the first passageway.

The exhaust gas is flowed into the first passageway at 706. In variousembodiments, the reductant is inserted into the first passageway afterthe exhaust gas flow into the first passageway has initiated. The firstpassageway is structured to direct the flow of the exhaust gas in afirst direction towards the second passageway. The second passageway isstructured to redirect the flow of the exhaust gas in a second directionsubstantially opposite the first direction, for example a change indirection of the exhaust gas flow from the first direction to the seconddirection of greater than about 90 degrees (e.g., about 100 degrees, 110degrees, 120 degrees, 130 degrees, 140 degrees, 150 degrees, 160degrees, 170 degrees, or about 180 degrees) towards the thirdpassageway.

The third passageway is structured to redirect the flow of the exhaustgas in a third direction substantially opposite the second direction,for example, a change in direction of the exhaust gas flow from thefirst direction to the second direction of greater than about 90 degrees(e.g., about 100 degrees, 110 degrees, 120 degrees, 130 degrees, 140degrees, 150 degrees, 160 degrees, 170 degrees, or about 180 degrees)towards the SCR system. Flowing the exhaust gas through the firstpassageway, the second passageway and the third passageway increases theresidence time of the exhaust gas in the mixer. The increase inresidence time provides better mixing of the reductant inserted into themixer with the exhaust gas which can contribute to increasing acatalytic conversion efficiency of the SCR system.

As used herein, the terms “about” and “approximately” generally meanplus or minus 10% of the stated value. For example, about 0.5 wouldinclude 0.45 and 0.55, about 10 would include 9 to 11, about 1000 wouldinclude 900 to 1100.

As used herein, the singular forms “a”, “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, the term “a member” is intended to mean a single member or acombination of members, “a material” is intended to mean one or morematerials, or a combination thereof.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like as used herein mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or moveable (e.g., removableor releasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

It is important to note that the construction and arrangement of thevarious exemplary embodiments are illustrative only. Although only a fewembodiments have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Othersubstitutions, modifications, changes and omissions may also be made inthe design, operating conditions and arrangement of the variousexemplary embodiments without departing from the scope of the presentinvention.

1.-21. (canceled)
 22. A method of promoting mixing of a reductant withan exhaust gas flowing through an aftertreatment system including atleast a selective catalytic reduction system, comprising; positioning amixer upstream of the selective catalytic reduction system, the mixerincluding a housing defining an internal volume, the housing includingat least a first passageway, a second passageway, a third passageway andan injection port defined on a sidewall of the housing proximate to thefirst passageway; inserting the reductant into the first passageway viathe injection port; and flowing the exhaust gas into the firstpassageway, the first passageway structured to direct the flow in afirst direction towards the second passageway, the second passagewaystructured to redirect the flow in a second direction substantiallyopposite the first direction towards the third passageway, and the thirdpassageway structured to redirect the flow in a third directionsubstantially opposite the second direction towards the selectivecatalytic reduction system.
 23. The method of claim 22, wherein themixer includes a first partition wall and a second partition wallpositioned in the internal volume defined by the housing, the firstpartition wall and the second partition wall oriented to define thefirst passageway, the second passageway and the third passageway. 24.The method of claim 23, wherein the first partition wall and the secondpartition wall are positioned parallel to each other.
 25. The method ofclaim 23, wherein the first partition wall and the second partition wallare substantially arcuate.